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   1 /*********************************************************************
   2  *
   3  * Filename:      irlap_frame.c
   4  * Version:       1.0
   5  * Description:   Build and transmit IrLAP frames
   6  * Status:        Stable
   7  * Author:        Dag Brattli <dagb@cs.uit.no>
   8  * Created at:    Tue Aug 19 10:27:26 1997
   9  * Modified at:   Wed Jan  5 08:59:04 2000
  10  * Modified by:   Dag Brattli <dagb@cs.uit.no>
  11  *
  12  *     Copyright (c) 1998-2000 Dag Brattli <dagb@cs.uit.no>,
  13  *     All Rights Reserved.
  14  *     Copyright (c) 2000-2003 Jean Tourrilhes <jt@hpl.hp.com>
  15  *
  16  *     This program is free software; you can redistribute it and/or
  17  *     modify it under the terms of the GNU General Public License as
  18  *     published by the Free Software Foundation; either version 2 of
  19  *     the License, or (at your option) any later version.
  20  *
  21  *     Neither Dag Brattli nor University of Tromsø admit liability nor
  22  *     provide warranty for any of this software. This material is
  23  *     provided "AS-IS" and at no charge.
  24  *
  25  ********************************************************************/
  26
  27 #include <linux/skbuff.h>
  28 #include <linux/if.h>
  29 #include <linux/if_ether.h>
  30 #include <linux/netdevice.h>
  31 #include <linux/irda.h>
  32
  33 #include <net/pkt_sched.h>
  34 #include <net/sock.h>
  35
  36 #include <asm/byteorder.h>
  37
  38 #include <net/irda/irda.h>
  39 #include <net/irda/irda_device.h>
  40 #include <net/irda/irlap.h>
  41 #include <net/irda/wrapper.h>
  42 #include <net/irda/timer.h>
  43 #include <net/irda/irlap_frame.h>
  44 #include <net/irda/qos.h>
  45
  46 static void irlap_send_i_frame(struct irlap_cb *self, struct sk_buff *skb,
  47                                int command);
  48
  49 /*
  50  * Function irlap_insert_info (self, skb)
  51  *
  52  *    Insert minimum turnaround time and speed information into the skb. We
  53  *    need to do this since it's per packet relevant information. Safe to
  54  *    have this function inlined since it's only called from one place
  55  */
  56 static inline void irlap_insert_info(struct irlap_cb *self,
  57                                      struct sk_buff *skb)
  58 {
  59         struct irda_skb_cb *cb = (struct irda_skb_cb *) skb->cb;
  60
  61         /*
  62          * Insert MTT (min. turn time) and speed into skb, so that the
  63          * device driver knows which settings to use
  64          */
  65         cb->magic = LAP_MAGIC;
  66         cb->mtt = self->mtt_required;
  67         cb->next_speed = self->speed;
  68
  69         /* Reset */
  70         self->mtt_required = 0;
  71
  72         /*
  73          * Delay equals negotiated BOFs count, plus the number of BOFs to
  74          * force the negotiated minimum turnaround time
  75          */
  76         cb->xbofs = self->bofs_count;
  77         cb->next_xbofs = self->next_bofs;
  78         cb->xbofs_delay = self->xbofs_delay;
  79
  80         /* Reset XBOF's delay (used only for getting min turn time) */
  81         self->xbofs_delay = 0;
  82         /* Put the correct xbofs value for the next packet */
  83         self->bofs_count = self->next_bofs;
  84 }
  85
  86 /*
  87  * Function irlap_queue_xmit (self, skb)
  88  *
  89  *    A little wrapper for dev_queue_xmit, so we can insert some common
  90  *    code into it.
  91  */
  92 void irlap_queue_xmit(struct irlap_cb *self, struct sk_buff *skb)
  93 {
  94         /* Some common init stuff */
  95         skb->dev = self->netdev;
  96         skb->h.raw = skb->nh.raw = skb->mac.raw = skb->data;
  97         skb->protocol = htons(ETH_P_IRDA);
  98         skb->priority = TC_PRIO_BESTEFFORT;
  99
 100         irlap_insert_info(self, skb);
 101
 102         dev_queue_xmit(skb);
 103 }
 104
 105 /*
 106  * Function irlap_send_snrm_cmd (void)
 107  *
 108  *    Transmits a connect SNRM command frame
 109  */
 110 void irlap_send_snrm_frame(struct irlap_cb *self, struct qos_info *qos)
 111 {
 112         struct sk_buff *tx_skb;
 113         struct snrm_frame *frame;
 114         int ret;
 115
 116         IRDA_ASSERT(self != NULL, return;);
 117         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 118
 119         /* Allocate frame */
 120         tx_skb = dev_alloc_skb(64);
 121         if (!tx_skb)
 122                 return;
 123
 124         frame = (struct snrm_frame *) skb_put(tx_skb, 2);
 125
 126         /* Insert connection address field */
 127         if (qos)
 128                 frame->caddr = CMD_FRAME | CBROADCAST;
 129         else
 130                 frame->caddr = CMD_FRAME | self->caddr;
 131
 132         /* Insert control field */
 133         frame->control = SNRM_CMD | PF_BIT;
 134
 135         /*
 136          *  If we are establishing a connection then insert QoS paramerters
 137          */
 138         if (qos) {
 139                 skb_put(tx_skb, 9); /* 21 left */
 140                 frame->saddr = cpu_to_le32(self->saddr);
 141                 frame->daddr = cpu_to_le32(self->daddr);
 142
 143                 frame->ncaddr = self->caddr;
 144
 145                 ret = irlap_insert_qos_negotiation_params(self, tx_skb);
 146                 if (ret < 0) {
 147                         dev_kfree_skb(tx_skb);
 148                         return;
 149                 }
 150         }
 151         irlap_queue_xmit(self, tx_skb);
 152 }
 153
 154 /*
 155  * Function irlap_recv_snrm_cmd (skb, info)
 156  *
 157  *    Received SNRM (Set Normal Response Mode) command frame
 158  *
 159  */
 160 static void irlap_recv_snrm_cmd(struct irlap_cb *self, struct sk_buff *skb,
 161                                 struct irlap_info *info)
 162 {
 163         struct snrm_frame *frame;
 164
 165         if (pskb_may_pull(skb,sizeof(struct snrm_frame))) {
 166                 frame = (struct snrm_frame *) skb->data;
 167
 168                 /* Copy the new connection address ignoring the C/R bit */
 169                 info->caddr = frame->ncaddr & 0xFE;
 170
 171                 /* Check if the new connection address is valid */
 172                 if ((info->caddr == 0x00) || (info->caddr == 0xfe)) {
 173                         IRDA_DEBUG(3, "%s(), invalid connection address!\n",
 174                                    __FUNCTION__);
 175                         return;
 176                 }
 177
 178                 /* Copy peer device address */
 179                 info->daddr = le32_to_cpu(frame->saddr);
 180                 info->saddr = le32_to_cpu(frame->daddr);
 181
 182                 /* Only accept if addressed directly to us */
 183                 if (info->saddr != self->saddr) {
 184                         IRDA_DEBUG(2, "%s(), not addressed to us!\n",
 185                                    __FUNCTION__);
 186                         return;
 187                 }
 188                 irlap_do_event(self, RECV_SNRM_CMD, skb, info);
 189         } else {
 190                 /* Signal that this SNRM frame does not contain and I-field */
 191                 irlap_do_event(self, RECV_SNRM_CMD, skb, NULL);
 192         }
 193 }
 194
 195 /*
 196  * Function irlap_send_ua_response_frame (qos)
 197  *
 198  *    Send UA (Unnumbered Acknowledgement) frame
 199  *
 200  */
 201 void irlap_send_ua_response_frame(struct irlap_cb *self, struct qos_info *qos)
 202 {
 203         struct sk_buff *tx_skb;
 204         struct ua_frame *frame;
 205         int ret;
 206
 207         IRDA_DEBUG(2, "%s() <%ld>\n", __FUNCTION__, jiffies);
 208
 209         IRDA_ASSERT(self != NULL, return;);
 210         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 211
 212         /* Allocate frame */
 213         tx_skb = dev_alloc_skb(64);
 214         if (!tx_skb)
 215                 return;
 216
 217         frame = (struct ua_frame *) skb_put(tx_skb, 10);
 218
 219         /* Build UA response */
 220         frame->caddr = self->caddr;
 221         frame->control = UA_RSP | PF_BIT;
 222
 223         frame->saddr = cpu_to_le32(self->saddr);
 224         frame->daddr = cpu_to_le32(self->daddr);
 225
 226         /* Should we send QoS negotiation parameters? */
 227         if (qos) {
 228                 ret = irlap_insert_qos_negotiation_params(self, tx_skb);
 229                 if (ret < 0) {
 230                         dev_kfree_skb(tx_skb);
 231                         return;
 232                 }
 233         }
 234
 235         irlap_queue_xmit(self, tx_skb);
 236 }
 237
 238
 239 /*
 240  * Function irlap_send_dm_frame (void)
 241  *
 242  *    Send disconnected mode (DM) frame
 243  *
 244  */
 245 void irlap_send_dm_frame( struct irlap_cb *self)
 246 {
 247         struct sk_buff *tx_skb = NULL;
 248         __u8 *frame;
 249
 250         IRDA_ASSERT(self != NULL, return;);
 251         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 252
 253         tx_skb = dev_alloc_skb(32);
 254         if (!tx_skb)
 255                 return;
 256
 257         frame = skb_put(tx_skb, 2);
 258
 259         if (self->state == LAP_NDM)
 260                 frame[0] = CBROADCAST;
 261         else
 262                 frame[0] = self->caddr;
 263
 264         frame[1] = DM_RSP | PF_BIT;
 265
 266         irlap_queue_xmit(self, tx_skb);
 267 }
 268
 269 /*
 270  * Function irlap_send_disc_frame (void)
 271  *
 272  *    Send disconnect (DISC) frame
 273  *
 274  */
 275 void irlap_send_disc_frame(struct irlap_cb *self)
 276 {
 277         struct sk_buff *tx_skb = NULL;
 278         __u8 *frame;
 279
 280         IRDA_DEBUG(3, "%s()\n", __FUNCTION__);
 281
 282         IRDA_ASSERT(self != NULL, return;);
 283         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 284
 285         tx_skb = dev_alloc_skb(16);
 286         if (!tx_skb)
 287                 return;
 288
 289         frame = skb_put(tx_skb, 2);
 290
 291         frame[0] = self->caddr | CMD_FRAME;
 292         frame[1] = DISC_CMD | PF_BIT;
 293
 294         irlap_queue_xmit(self, tx_skb);
 295 }
 296
 297 /*
 298  * Function irlap_send_discovery_xid_frame (S, s, command)
 299  *
 300  *    Build and transmit a XID (eXchange station IDentifier) discovery
 301  *    frame.
 302  */
 303 void irlap_send_discovery_xid_frame(struct irlap_cb *self, int S, __u8 s,
 304                                     __u8 command, discovery_t *discovery)
 305 {
 306         struct sk_buff *tx_skb = NULL;
 307         struct xid_frame *frame;
 308         __u32 bcast = BROADCAST;
 309         __u8 *info;
 310
 311         IRDA_DEBUG(4, "%s(), s=%d, S=%d, command=%d\n", __FUNCTION__,
 312                    s, S, command);
 313
 314         IRDA_ASSERT(self != NULL, return;);
 315         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 316         IRDA_ASSERT(discovery != NULL, return;);
 317
 318         tx_skb = dev_alloc_skb(64);
 319         if (!tx_skb)
 320                 return;
 321
 322         skb_put(tx_skb, 14);
 323         frame = (struct xid_frame *) tx_skb->data;
 324
 325         if (command) {
 326                 frame->caddr = CBROADCAST | CMD_FRAME;
 327                 frame->control =  XID_CMD | PF_BIT;
 328         } else {
 329                 frame->caddr = CBROADCAST;
 330                 frame->control =  XID_RSP | PF_BIT;
 331         }
 332         frame->ident = XID_FORMAT;
 333
 334         frame->saddr = cpu_to_le32(self->saddr);
 335
 336         if (command)
 337                 frame->daddr = cpu_to_le32(bcast);
 338         else
 339                 frame->daddr = cpu_to_le32(discovery->data.daddr);
 340
 341         switch (S) {
 342         case 1:
 343                 frame->flags = 0x00;
 344                 break;
 345         case 6:
 346                 frame->flags = 0x01;
 347                 break;
 348         case 8:
 349                 frame->flags = 0x02;
 350                 break;
 351         case 16:
 352                 frame->flags = 0x03;
 353                 break;
 354         default:
 355                 frame->flags = 0x02;
 356                 break;
 357         }
 358
 359         frame->slotnr = s;
 360         frame->version = 0x00;
 361
 362         /*
 363          *  Provide info for final slot only in commands, and for all
 364          *  responses. Send the second byte of the hint only if the
 365          *  EXTENSION bit is set in the first byte.
 366          */
 367         if (!command || (frame->slotnr == 0xff)) {
 368                 int len;
 369
 370                 if (discovery->data.hints[0] & HINT_EXTENSION) {
 371                         info = skb_put(tx_skb, 2);
 372                         info[0] = discovery->data.hints[0];
 373                         info[1] = discovery->data.hints[1];
 374                 } else {
 375                         info = skb_put(tx_skb, 1);
 376                         info[0] = discovery->data.hints[0];
 377                 }
 378                 info = skb_put(tx_skb, 1);
 379                 info[0] = discovery->data.charset;
 380
 381                 len = IRDA_MIN(discovery->name_len, skb_tailroom(tx_skb));
 382                 info = skb_put(tx_skb, len);
 383                 memcpy(info, discovery->data.info, len);
 384         }
 385         irlap_queue_xmit(self, tx_skb);
 386 }
 387
 388 /*
 389  * Function irlap_recv_discovery_xid_rsp (skb, info)
 390  *
 391  *    Received a XID discovery response
 392  *
 393  */
 394 static void irlap_recv_discovery_xid_rsp(struct irlap_cb *self,
 395                                          struct sk_buff *skb,
 396                                          struct irlap_info *info)
 397 {
 398         struct xid_frame *xid;
 399         discovery_t *discovery = NULL;
 400         __u8 *discovery_info;
 401         char *text;
 402
 403         IRDA_DEBUG(4, "%s()\n", __FUNCTION__);
 404
 405         IRDA_ASSERT(self != NULL, return;);
 406         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 407
 408         if (!pskb_may_pull(skb, sizeof(struct xid_frame))) {
 409                 IRDA_ERROR("%s: frame to short!\n", __FUNCTION__);
 410                 return;
 411         }
 412
 413         xid = (struct xid_frame *) skb->data;
 414
 415         info->daddr = le32_to_cpu(xid->saddr);
 416         info->saddr = le32_to_cpu(xid->daddr);
 417
 418         /* Make sure frame is addressed to us */
 419         if ((info->saddr != self->saddr) && (info->saddr != BROADCAST)) {
 420                 IRDA_DEBUG(0, "%s(), frame is not addressed to us!\n",
 421                            __FUNCTION__);
 422                 return;
 423         }
 424
 425         if ((discovery = kmalloc(sizeof(discovery_t), GFP_ATOMIC)) == NULL) {
 426                 IRDA_WARNING("%s: kmalloc failed!\n", __FUNCTION__);
 427                 return;
 428         }
 429         memset(discovery, 0, sizeof(discovery_t));
 430
 431         discovery->data.daddr = info->daddr;
 432         discovery->data.saddr = self->saddr;
 433         discovery->timestamp = jiffies;
 434
 435         IRDA_DEBUG(4, "%s(), daddr=%08x\n", __FUNCTION__,
 436                    discovery->data.daddr);
 437
 438         discovery_info = skb_pull(skb, sizeof(struct xid_frame));
 439
 440         /* Get info returned from peer */
 441         discovery->data.hints[0] = discovery_info[0];
 442         if (discovery_info[0] & HINT_EXTENSION) {
 443                 IRDA_DEBUG(4, "EXTENSION\n");
 444                 discovery->data.hints[1] = discovery_info[1];
 445                 discovery->data.charset = discovery_info[2];
 446                 text = (char *) &discovery_info[3];
 447         } else {
 448                 discovery->data.hints[1] = 0;
 449                 discovery->data.charset = discovery_info[1];
 450                 text = (char *) &discovery_info[2];
 451         }
 452         /*
 453          *  Terminate info string, should be safe since this is where the
 454          *  FCS bytes resides.
 455          */
 456         skb->data[skb->len] = '\0';
 457         strncpy(discovery->data.info, text, NICKNAME_MAX_LEN);
 458         discovery->name_len = strlen(discovery->data.info);
 459
 460         info->discovery = discovery;
 461
 462         irlap_do_event(self, RECV_DISCOVERY_XID_RSP, skb, info);
 463 }
 464
 465 /*
 466  * Function irlap_recv_discovery_xid_cmd (skb, info)
 467  *
 468  *    Received a XID discovery command
 469  *
 470  */
 471 static void irlap_recv_discovery_xid_cmd(struct irlap_cb *self,
 472                                          struct sk_buff *skb,
 473                                          struct irlap_info *info)
 474 {
 475         struct xid_frame *xid;
 476         discovery_t *discovery = NULL;
 477         __u8 *discovery_info;
 478         char *text;
 479
 480         if (!pskb_may_pull(skb, sizeof(struct xid_frame))) {
 481                 IRDA_ERROR("%s: frame to short!\n", __FUNCTION__);
 482                 return;
 483         }
 484
 485         xid = (struct xid_frame *) skb->data;
 486
 487         info->daddr = le32_to_cpu(xid->saddr);
 488         info->saddr = le32_to_cpu(xid->daddr);
 489
 490         /* Make sure frame is addressed to us */
 491         if ((info->saddr != self->saddr) && (info->saddr != BROADCAST)) {
 492                 IRDA_DEBUG(0, "%s(), frame is not addressed to us!\n",
 493                            __FUNCTION__);
 494                 return;
 495         }
 496
 497         switch (xid->flags & 0x03) {
 498         case 0x00:
 499                 info->S = 1;
 500                 break;
 501         case 0x01:
 502                 info->S = 6;
 503                 break;
 504         case 0x02:
 505                 info->S = 8;
 506                 break;
 507         case 0x03:
 508                 info->S = 16;
 509                 break;
 510         default:
 511                 /* Error!! */
 512                 return;
 513         }
 514         info->s = xid->slotnr;
 515
 516         discovery_info = skb_pull(skb, sizeof(struct xid_frame));
 517
 518         /*
 519          *  Check if last frame
 520          */
 521         if (info->s == 0xff) {
 522                 /* Check if things are sane at this point... */
 523                 if((discovery_info == NULL) ||
 524                    !pskb_may_pull(skb, 3)) {
 525                         IRDA_ERROR("%s: discovery frame to short!\n",
 526                                    __FUNCTION__);
 527                         return;
 528                 }
 529
 530                 /*
 531                  *  We now have some discovery info to deliver!
 532                  */
 533                 discovery = kmalloc(sizeof(discovery_t), GFP_ATOMIC);
 534                 if (!discovery) {
 535                         IRDA_WARNING("%s: unable to malloc!\n", __FUNCTION__);
 536                         return;
 537                 }
 538
 539                 discovery->data.daddr = info->daddr;
 540                 discovery->data.saddr = self->saddr;
 541                 discovery->timestamp = jiffies;
 542
 543                 discovery->data.hints[0] = discovery_info[0];
 544                 if (discovery_info[0] & HINT_EXTENSION) {
 545                         discovery->data.hints[1] = discovery_info[1];
 546                         discovery->data.charset = discovery_info[2];
 547                         text = (char *) &discovery_info[3];
 548                 } else {
 549                         discovery->data.hints[1] = 0;
 550                         discovery->data.charset = discovery_info[1];
 551                         text = (char *) &discovery_info[2];
 552                 }
 553                 /*
 554                  *  Terminate string, should be safe since this is where the
 555                  *  FCS bytes resides.
 556                  */
 557                 skb->data[skb->len] = '\0';
 558                 strncpy(discovery->data.info, text, NICKNAME_MAX_LEN);
 559                 discovery->name_len = strlen(discovery->data.info);
 560
 561                 info->discovery = discovery;
 562         } else
 563                 info->discovery = NULL;
 564
 565         irlap_do_event(self, RECV_DISCOVERY_XID_CMD, skb, info);
 566 }
 567
 568 /*
 569  * Function irlap_send_rr_frame (self, command)
 570  *
 571  *    Build and transmit RR (Receive Ready) frame. Notice that it is currently
 572  *    only possible to send RR frames with the poll bit set.
 573  */
 574 void irlap_send_rr_frame(struct irlap_cb *self, int command)
 575 {
 576         struct sk_buff *tx_skb;
 577         __u8 *frame;
 578
 579         tx_skb = dev_alloc_skb(16);
 580         if (!tx_skb)
 581                 return;
 582
 583         frame = skb_put(tx_skb, 2);
 584
 585         frame[0] = self->caddr;
 586         frame[0] |= (command) ? CMD_FRAME : 0;
 587
 588         frame[1] = RR | PF_BIT | (self->vr << 5);
 589
 590         irlap_queue_xmit(self, tx_skb);
 591 }
 592
 593 /*
 594  * Function irlap_send_rd_frame (self)
 595  *
 596  *    Request disconnect. Used by a secondary station to request the
 597  *    disconnection of the link.
 598  */
 599 void irlap_send_rd_frame(struct irlap_cb *self)
 600 {
 601         struct sk_buff *tx_skb;
 602         __u8 *frame;
 603
 604         tx_skb = dev_alloc_skb(16);
 605         if (!tx_skb)
 606                 return;
 607
 608         frame = skb_put(tx_skb, 2);
 609
 610         frame[0] = self->caddr;
 611         frame[1] = RD_RSP | PF_BIT;
 612
 613         irlap_queue_xmit(self, tx_skb);
 614 }
 615
 616 /*
 617  * Function irlap_recv_rr_frame (skb, info)
 618  *
 619  *    Received RR (Receive Ready) frame from peer station, no harm in
 620  *    making it inline since its called only from one single place
 621  *    (irlap_driver_rcv).
 622  */
 623 static inline void irlap_recv_rr_frame(struct irlap_cb *self,
 624                                        struct sk_buff *skb,
 625                                        struct irlap_info *info, int command)
 626 {
 627         info->nr = skb->data[1] >> 5;
 628
 629         /* Check if this is a command or a response frame */
 630         if (command)
 631                 irlap_do_event(self, RECV_RR_CMD, skb, info);
 632         else
 633                 irlap_do_event(self, RECV_RR_RSP, skb, info);
 634 }
 635
 636 /*
 637  * Function irlap_recv_rnr_frame (self, skb, info)
 638  *
 639  *    Received RNR (Receive Not Ready) frame from peer station
 640  *
 641  */
 642 static void irlap_recv_rnr_frame(struct irlap_cb *self, struct sk_buff *skb,
 643                                  struct irlap_info *info, int command)
 644 {
 645         info->nr = skb->data[1] >> 5;
 646
 647         IRDA_DEBUG(4, "%s(), nr=%d, %ld\n", __FUNCTION__, info->nr, jiffies);
 648
 649         if (command)
 650                 irlap_do_event(self, RECV_RNR_CMD, skb, info);
 651         else
 652                 irlap_do_event(self, RECV_RNR_RSP, skb, info);
 653 }
 654
 655 static void irlap_recv_rej_frame(struct irlap_cb *self, struct sk_buff *skb,
 656                                  struct irlap_info *info, int command)
 657 {
 658         IRDA_DEBUG(0, "%s()\n", __FUNCTION__);
 659
 660         info->nr = skb->data[1] >> 5;
 661
 662         /* Check if this is a command or a response frame */
 663         if (command)
 664                 irlap_do_event(self, RECV_REJ_CMD, skb, info);
 665         else
 666                 irlap_do_event(self, RECV_REJ_RSP, skb, info);
 667 }
 668
 669 static void irlap_recv_srej_frame(struct irlap_cb *self, struct sk_buff *skb,
 670                                   struct irlap_info *info, int command)
 671 {
 672         IRDA_DEBUG(0, "%s()\n", __FUNCTION__);
 673
 674         info->nr = skb->data[1] >> 5;
 675
 676         /* Check if this is a command or a response frame */
 677         if (command)
 678                 irlap_do_event(self, RECV_SREJ_CMD, skb, info);
 679         else
 680                 irlap_do_event(self, RECV_SREJ_RSP, skb, info);
 681 }
 682
 683 static void irlap_recv_disc_frame(struct irlap_cb *self, struct sk_buff *skb,
 684                                   struct irlap_info *info, int command)
 685 {
 686         IRDA_DEBUG(2, "%s()\n", __FUNCTION__);
 687
 688         /* Check if this is a command or a response frame */
 689         if (command)
 690                 irlap_do_event(self, RECV_DISC_CMD, skb, info);
 691         else
 692                 irlap_do_event(self, RECV_RD_RSP, skb, info);
 693 }
 694
 695 /*
 696  * Function irlap_recv_ua_frame (skb, frame)
 697  *
 698  *    Received UA (Unnumbered Acknowledgement) frame
 699  *
 700  */
 701 static inline void irlap_recv_ua_frame(struct irlap_cb *self,
 702                                        struct sk_buff *skb,
 703                                        struct irlap_info *info)
 704 {
 705         irlap_do_event(self, RECV_UA_RSP, skb, info);
 706 }
 707
 708 /*
 709  * Function irlap_send_data_primary(self, skb)
 710  *
 711  *    Send I-frames as the primary station but without the poll bit set
 712  *
 713  */
 714 void irlap_send_data_primary(struct irlap_cb *self, struct sk_buff *skb)
 715 {
 716         struct sk_buff *tx_skb;
 717
 718         if (skb->data[1] == I_FRAME) {
 719
 720                 /*
 721                  *  Insert frame sequence number (Vs) in control field before
 722                  *  inserting into transmit window queue.
 723                  */
 724                 skb->data[1] = I_FRAME | (self->vs << 1);
 725
 726                 /*
 727                  *  Insert frame in store, in case of retransmissions
 728                  *  Increase skb reference count, see irlap_do_event()
 729                  */
 730                 skb_get(skb);
 731                 skb_queue_tail(&self->wx_list, skb);
 732
 733                 /* Copy buffer */
 734                 tx_skb = skb_clone(skb, GFP_ATOMIC);
 735                 if (tx_skb == NULL) {
 736                         return;
 737                 }
 738
 739                 self->vs = (self->vs + 1) % 8;
 740                 self->ack_required = FALSE;
 741                 self->window -= 1;
 742
 743                 irlap_send_i_frame( self, tx_skb, CMD_FRAME);
 744         } else {
 745                 IRDA_DEBUG(4, "%s(), sending unreliable frame\n", __FUNCTION__);
 746                 irlap_send_ui_frame(self, skb_get(skb), self->caddr, CMD_FRAME);
 747                 self->window -= 1;
 748         }
 749 }
 750 /*
 751  * Function irlap_send_data_primary_poll (self, skb)
 752  *
 753  *    Send I(nformation) frame as primary with poll bit set
 754  */
 755 void irlap_send_data_primary_poll(struct irlap_cb *self, struct sk_buff *skb)
 756 {
 757         struct sk_buff *tx_skb;
 758         int transmission_time;
 759
 760         /* Stop P timer */
 761         del_timer(&self->poll_timer);
 762
 763         /* Is this reliable or unreliable data? */
 764         if (skb->data[1] == I_FRAME) {
 765
 766                 /*
 767                  *  Insert frame sequence number (Vs) in control field before
 768                  *  inserting into transmit window queue.
 769                  */
 770                 skb->data[1] = I_FRAME | (self->vs << 1);
 771
 772                 /*
 773                  *  Insert frame in store, in case of retransmissions
 774                  *  Increase skb reference count, see irlap_do_event()
 775                  */
 776                 skb_get(skb);
 777                 skb_queue_tail(&self->wx_list, skb);
 778
 779                 /* Copy buffer */
 780                 tx_skb = skb_clone(skb, GFP_ATOMIC);
 781                 if (tx_skb == NULL) {
 782                         return;
 783                 }
 784
 785                 /*
 786                  *  Set poll bit if necessary. We do this to the copied
 787                  *  skb, since retransmitted need to set or clear the poll
 788                  *  bit depending on when they are sent.
 789                  */
 790                 tx_skb->data[1] |= PF_BIT;
 791
 792                 self->vs = (self->vs + 1) % 8;
 793                 self->ack_required = FALSE;
 794
 795                 irlap_send_i_frame(self, tx_skb, CMD_FRAME);
 796         } else {
 797                 IRDA_DEBUG(4, "%s(), sending unreliable frame\n", __FUNCTION__);
 798
 799                 if (self->ack_required) {
 800                         irlap_send_ui_frame(self, skb_get(skb), self->caddr, CMD_FRAME);
 801                         irlap_send_rr_frame(self, CMD_FRAME);
 802                         self->ack_required = FALSE;
 803                 } else {
 804                         skb->data[1] |= PF_BIT;
 805                         irlap_send_ui_frame(self, skb_get(skb), self->caddr, CMD_FRAME);
 806                 }
 807         }
 808
 809         /* How much time we took for transmission of all frames.
 810          * We don't know, so let assume we used the full window. Jean II */
 811         transmission_time = self->final_timeout;
 812
 813         /* Reset parameter so that we can fill next window */
 814         self->window = self->window_size;
 815
 816 #ifdef CONFIG_IRDA_DYNAMIC_WINDOW
 817         /* Remove what we have not used. Just do a prorata of the
 818          * bytes left in window to window capacity.
 819          * See max_line_capacities[][] in qos.c for details. Jean II */
 820         transmission_time -= (self->final_timeout * self->bytes_left
 821                               / self->line_capacity);
 822         IRDA_DEBUG(4, "%s() adjusting transmission_time : ft=%d, bl=%d, lc=%d -> tt=%d\n", __FUNCTION__, self->final_timeout, self->bytes_left, self->line_capacity, transmission_time);
 823
 824         /* We are allowed to transmit a maximum number of bytes again. */
 825         self->bytes_left = self->line_capacity;
 826 #endif /* CONFIG_IRDA_DYNAMIC_WINDOW */
 827
 828         /*
 829          * The network layer has a intermediate buffer between IrLAP
 830          * and the IrDA driver which can contain 8 frames. So, even
 831          * though IrLAP is currently sending the *last* frame of the
 832          * tx-window, the driver most likely has only just started
 833          * sending the *first* frame of the same tx-window.
 834          * I.e. we are always at the very begining of or Tx window.
 835          * Now, we are supposed to set the final timer from the end
 836          * of our tx-window to let the other peer reply. So, we need
 837          * to add extra time to compensate for the fact that we
 838          * are really at the start of tx-window, otherwise the final timer
 839          * might expire before he can answer...
 840          * Jean II
 841          */
 842         irlap_start_final_timer(self, self->final_timeout + transmission_time);
 843
 844         /*
 845          * The clever amongst you might ask why we do this adjustement
 846          * only here, and not in all the other cases in irlap_event.c.
 847          * In all those other case, we only send a very short management
 848          * frame (few bytes), so the adjustement would be lost in the
 849          * noise...
 850          * The exception of course is irlap_resend_rejected_frame().
 851          * Jean II */
 852 }
 853
 854 /*
 855  * Function irlap_send_data_secondary_final (self, skb)
 856  *
 857  *    Send I(nformation) frame as secondary with final bit set
 858  *
 859  */
 860 void irlap_send_data_secondary_final(struct irlap_cb *self,
 861                                      struct sk_buff *skb)
 862 {
 863         struct sk_buff *tx_skb = NULL;
 864
 865         IRDA_ASSERT(self != NULL, return;);
 866         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 867         IRDA_ASSERT(skb != NULL, return;);
 868
 869         /* Is this reliable or unreliable data? */
 870         if (skb->data[1] == I_FRAME) {
 871
 872                 /*
 873                  *  Insert frame sequence number (Vs) in control field before
 874                  *  inserting into transmit window queue.
 875                  */
 876                 skb->data[1] = I_FRAME | (self->vs << 1);
 877
 878                 /*
 879                  *  Insert frame in store, in case of retransmissions
 880                  *  Increase skb reference count, see irlap_do_event()
 881                  */
 882                 skb_get(skb);
 883                 skb_queue_tail(&self->wx_list, skb);
 884
 885                 tx_skb = skb_clone(skb, GFP_ATOMIC);
 886                 if (tx_skb == NULL) {
 887                         return;
 888                 }
 889
 890                 tx_skb->data[1] |= PF_BIT;
 891
 892                 self->vs = (self->vs + 1) % 8;
 893                 self->ack_required = FALSE;
 894
 895                 irlap_send_i_frame(self, tx_skb, RSP_FRAME);
 896         } else {
 897                 if (self->ack_required) {
 898                         irlap_send_ui_frame(self, skb_get(skb), self->caddr, RSP_FRAME);
 899                         irlap_send_rr_frame(self, RSP_FRAME);
 900                         self->ack_required = FALSE;
 901                 } else {
 902                         skb->data[1] |= PF_BIT;
 903                         irlap_send_ui_frame(self, skb_get(skb), self->caddr, RSP_FRAME);
 904                 }
 905         }
 906
 907         self->window = self->window_size;
 908 #ifdef CONFIG_IRDA_DYNAMIC_WINDOW
 909         /* We are allowed to transmit a maximum number of bytes again. */
 910         self->bytes_left = self->line_capacity;
 911 #endif /* CONFIG_IRDA_DYNAMIC_WINDOW */
 912
 913         irlap_start_wd_timer(self, self->wd_timeout);
 914 }
 915
 916 /*
 917  * Function irlap_send_data_secondary (self, skb)
 918  *
 919  *    Send I(nformation) frame as secondary without final bit set
 920  *
 921  */
 922 void irlap_send_data_secondary(struct irlap_cb *self, struct sk_buff *skb)
 923 {
 924         struct sk_buff *tx_skb = NULL;
 925
 926         /* Is this reliable or unreliable data? */
 927         if (skb->data[1] == I_FRAME) {
 928
 929                 /*
 930                  *  Insert frame sequence number (Vs) in control field before
 931                  *  inserting into transmit window queue.
 932                  */
 933                 skb->data[1] = I_FRAME | (self->vs << 1);
 934
 935                 /*
 936                  *  Insert frame in store, in case of retransmissions
 937                  *  Increase skb reference count, see irlap_do_event()
 938                  */
 939                 skb_get(skb);
 940                 skb_queue_tail(&self->wx_list, skb);
 941
 942                 tx_skb = skb_clone(skb, GFP_ATOMIC);
 943                 if (tx_skb == NULL) {
 944                         return;
 945                 }
 946
 947                 self->vs = (self->vs + 1) % 8;
 948                 self->ack_required = FALSE;
 949                 self->window -= 1;
 950
 951                 irlap_send_i_frame(self, tx_skb, RSP_FRAME);
 952         } else {
 953                 irlap_send_ui_frame(self, skb_get(skb), self->caddr, RSP_FRAME);
 954                 self->window -= 1;
 955         }
 956 }
 957
 958 /*
 959  * Function irlap_resend_rejected_frames (nr)
 960  *
 961  *    Resend frames which has not been acknowledged. Should be safe to
 962  *    traverse the list without locking it since this function will only be
 963  *    called from interrupt context (BH)
 964  */
 965 void irlap_resend_rejected_frames(struct irlap_cb *self, int command)
 966 {
 967         struct sk_buff *tx_skb;
 968         struct sk_buff *skb;
 969         int count;
 970
 971         IRDA_ASSERT(self != NULL, return;);
 972         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 973
 974         /* Initialize variables */
 975         count = skb_queue_len(&self->wx_list);
 976
 977         /*  Resend unacknowledged frame(s) */
 978         skb = skb_peek(&self->wx_list);
 979         while (skb != NULL) {
 980                 irlap_wait_min_turn_around(self, &self->qos_tx);
 981
 982                 /* We copy the skb to be retransmitted since we will have to
 983                  * modify it. Cloning will confuse packet sniffers
 984                  */
 985                 /* tx_skb = skb_clone( skb, GFP_ATOMIC); */
 986                 tx_skb = skb_copy(skb, GFP_ATOMIC);
 987                 if (!tx_skb) {
 988                         IRDA_DEBUG(0, "%s(), unable to copy\n", __FUNCTION__);
 989                         return;
 990                 }
 991                 /* Unlink tx_skb from list */
 992                 tx_skb->next = tx_skb->prev = NULL;
 993                 tx_skb->list = NULL;
 994
 995                 /* Clear old Nr field + poll bit */
 996                 tx_skb->data[1] &= 0x0f;
 997
 998                 /*
 999                  *  Set poll bit on the last frame retransmitted
1000                  */
1001                 if (count-- == 1)
1002                         tx_skb->data[1] |= PF_BIT; /* Set p/f bit */
1003                 else
1004                         tx_skb->data[1] &= ~PF_BIT; /* Clear p/f bit */
1005
1006                 irlap_send_i_frame(self, tx_skb, command);
1007
1008                 /*
1009                  *  If our skb is the last buffer in the list, then
1010                  *  we are finished, if not, move to the next sk-buffer
1011                  */
1012                 if (skb == skb_peek_tail(&self->wx_list))
1013                         skb = NULL;
1014                 else
1015                         skb = skb->next;
1016         }
1017 #if 0 /* Not yet */
1018         /*
1019          *  We can now fill the window with additional data frames
1020          */
1021         while (skb_queue_len( &self->txq) > 0) {
1022
1023                 IRDA_DEBUG(0, "%s(), sending additional frames!\n", __FUNCTION__);
1024                 if ((skb_queue_len( &self->txq) > 0) &&
1025                     (self->window > 0)) {
1026                         skb = skb_dequeue( &self->txq);
1027                         IRDA_ASSERT(skb != NULL, return;);
1028
1029                         /*
1030                          *  If send window > 1 then send frame with pf
1031                          *  bit cleared
1032                          */
1033                         if ((self->window > 1) &&
1034                             skb_queue_len(&self->txq) > 0)
1035                         {
1036                                 irlap_send_data_primary(self, skb);
1037                         } else {
1038                                 irlap_send_data_primary_poll(self, skb);
1039                         }
1040                         kfree_skb(skb);
1041                 }
1042         }
1043 #endif
1044 }
1045
1046 void irlap_resend_rejected_frame(struct irlap_cb *self, int command)
1047 {
1048         struct sk_buff *tx_skb;
1049         struct sk_buff *skb;
1050
1051         IRDA_ASSERT(self != NULL, return;);
1052         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
1053
1054         /*  Resend unacknowledged frame(s) */
1055         skb = skb_peek(&self->wx_list);
1056         if (skb != NULL) {
1057                 irlap_wait_min_turn_around(self, &self->qos_tx);
1058
1059                 /* We copy the skb to be retransmitted since we will have to
1060                  * modify it. Cloning will confuse packet sniffers
1061                  */
1062                 /* tx_skb = skb_clone( skb, GFP_ATOMIC); */
1063                 tx_skb = skb_copy(skb, GFP_ATOMIC);
1064                 if (!tx_skb) {
1065                         IRDA_DEBUG(0, "%s(), unable to copy\n", __FUNCTION__);
1066                         return;
1067                 }
1068                 /* Unlink tx_skb from list */
1069                 tx_skb->next = tx_skb->prev = NULL;
1070                 tx_skb->list = NULL;
1071
1072                 /* Clear old Nr field + poll bit */
1073                 tx_skb->data[1] &= 0x0f;
1074
1075                 /*  Set poll/final bit */
1076                 tx_skb->data[1] |= PF_BIT; /* Set p/f bit */
1077
1078                 irlap_send_i_frame(self, tx_skb, command);
1079         }
1080 }
1081
1082 /*
1083  * Function irlap_send_ui_frame (self, skb, command)
1084  *
1085  *    Contruct and transmit an Unnumbered Information (UI) frame
1086  *
1087  */
1088 void irlap_send_ui_frame(struct irlap_cb *self, struct sk_buff *skb,
1089                          __u8 caddr, int command)
1090 {
1091         IRDA_DEBUG(4, "%s()\n", __FUNCTION__);
1092
1093         IRDA_ASSERT(self != NULL, return;);
1094         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
1095         IRDA_ASSERT(skb != NULL, return;);
1096
1097         /* Insert connection address */
1098         skb->data[0] = caddr | ((command) ? CMD_FRAME : 0);
1099
1100         irlap_queue_xmit(self, skb);
1101 }
1102
1103 /*
1104  * Function irlap_send_i_frame (skb)
1105  *
1106  *    Contruct and transmit Information (I) frame
1107  */
1108 static void irlap_send_i_frame(struct irlap_cb *self, struct sk_buff *skb,
1109                                int command)
1110 {
1111         /* Insert connection address */
1112         skb->data[0] = self->caddr;
1113         skb->data[0] |= (command) ? CMD_FRAME : 0;
1114
1115         /* Insert next to receive (Vr) */
1116         skb->data[1] |= (self->vr << 5);  /* insert nr */
1117
1118         irlap_queue_xmit(self, skb);
1119 }
1120
1121 /*
1122  * Function irlap_recv_i_frame (skb, frame)
1123  *
1124  *    Receive and parse an I (Information) frame, no harm in making it inline
1125  *    since it's called only from one single place (irlap_driver_rcv).
1126  */
1127 static inline void irlap_recv_i_frame(struct irlap_cb *self,
1128                                       struct sk_buff *skb,
1129                                       struct irlap_info *info, int command)
1130 {
1131         info->nr = skb->data[1] >> 5;          /* Next to receive */
1132         info->pf = skb->data[1] & PF_BIT;      /* Final bit */
1133         info->ns = (skb->data[1] >> 1) & 0x07; /* Next to send */
1134
1135         /* Check if this is a command or a response frame */
1136         if (command)
1137                 irlap_do_event(self, RECV_I_CMD, skb, info);
1138         else
1139                 irlap_do_event(self, RECV_I_RSP, skb, info);
1140 }
1141
1142 /*
1143  * Function irlap_recv_ui_frame (self, skb, info)
1144  *
1145  *    Receive and parse an Unnumbered Information (UI) frame
1146  *
1147  */
1148 static void irlap_recv_ui_frame(struct irlap_cb *self, struct sk_buff *skb,
1149                                 struct irlap_info *info)
1150 {
1151         IRDA_DEBUG( 4, "%s()\n", __FUNCTION__);
1152
1153         info->pf = skb->data[1] & PF_BIT;      /* Final bit */
1154
1155         irlap_do_event(self, RECV_UI_FRAME, skb, info);
1156 }
1157
1158 /*
1159  * Function irlap_recv_frmr_frame (skb, frame)
1160  *
1161  *    Received Frame Reject response.
1162  *
1163  */
1164 static void irlap_recv_frmr_frame(struct irlap_cb *self, struct sk_buff *skb,
1165                                   struct irlap_info *info)
1166 {
1167         __u8 *frame;
1168         int w, x, y, z;
1169
1170         IRDA_DEBUG(0, "%s()\n", __FUNCTION__);
1171
1172         IRDA_ASSERT(self != NULL, return;);
1173         IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
1174         IRDA_ASSERT(skb != NULL, return;);
1175         IRDA_ASSERT(info != NULL, return;);
1176
1177         if (!pskb_may_pull(skb, 4)) {
1178                 IRDA_ERROR("%s: frame to short!\n", __FUNCTION__);
1179                 return;
1180         }
1181
1182         frame = skb->data;
1183
1184         info->nr = frame[2] >> 5;          /* Next to receive */
1185         info->pf = frame[2] & PF_BIT;      /* Final bit */
1186         info->ns = (frame[2] >> 1) & 0x07; /* Next to send */
1187
1188         w = frame[3] & 0x01;
1189         x = frame[3] & 0x02;
1190         y = frame[3] & 0x04;
1191         z = frame[3] & 0x08;
1192
1193         if (w) {
1194                 IRDA_DEBUG(0, "Rejected control field is undefined or not "
1195                       "implemented.\n");
1196         }
1197         if (x) {
1198                 IRDA_DEBUG(0, "Rejected control field was invalid because it "
1199                       "contained a non permitted I field.\n");
1200         }
1201         if (y) {
1202                 IRDA_DEBUG(0, "Received I field exceeded the maximum negotiated "
1203                       "for the existing connection or exceeded the maximum "
1204                       "this station supports if no connection exists.\n");
1205         }
1206         if (z) {
1207                 IRDA_DEBUG(0, "Rejected control field control field contained an "
1208                       "invalid Nr count.\n");
1209         }
1210         irlap_do_event(self, RECV_FRMR_RSP, skb, info);
1211 }
1212
1213 /*
1214  * Function irlap_send_test_frame (self, daddr)
1215  *
1216  *    Send a test frame response
1217  *
1218  */
1219 void irlap_send_test_frame(struct irlap_cb *self, __u8 caddr, __u32 daddr,
1220                            struct sk_buff *cmd)
1221 {
1222         struct sk_buff *tx_skb;
1223         struct test_frame *frame;
1224         __u8 *info;
1225
1226         tx_skb = dev_alloc_skb(cmd->len+sizeof(struct test_frame));
1227         if (!tx_skb)
1228                 return;
1229
1230         /* Broadcast frames must include saddr and daddr fields */
1231         if (caddr == CBROADCAST) {
1232                 frame = (struct test_frame *)
1233                         skb_put(tx_skb, sizeof(struct test_frame));
1234
1235                 /* Insert the swapped addresses */
1236                 frame->saddr = cpu_to_le32(self->saddr);
1237                 frame->daddr = cpu_to_le32(daddr);
1238         } else
1239                 frame = (struct test_frame *) skb_put(tx_skb, LAP_ADDR_HEADER + LAP_CTRL_HEADER);
1240
1241         frame->caddr = caddr;
1242         frame->control = TEST_RSP | PF_BIT;
1243
1244         /* Copy info */
1245         info = skb_put(tx_skb, cmd->len);
1246         memcpy(info, cmd->data, cmd->len);
1247
1248         /* Return to sender */
1249         irlap_wait_min_turn_around(self, &self->qos_tx);
1250         irlap_queue_xmit(self, tx_skb);
1251 }
1252
1253 /*
1254  * Function irlap_recv_test_frame (self, skb)
1255  *
1256  *    Receive a test frame
1257  *
1258  */
1259 static void irlap_recv_test_frame(struct irlap_cb *self, struct sk_buff *skb,
1260                                   struct irlap_info *info, int command)
1261 {
1262         struct test_frame *frame;
1263
1264         IRDA_DEBUG(2, "%s()\n", __FUNCTION__);
1265
1266         if (!pskb_may_pull(skb, sizeof(*frame))) {
1267                 IRDA_ERROR("%s: frame to short!\n", __FUNCTION__);
1268                 return;
1269         }
1270         frame = (struct test_frame *) skb->data;
1271
1272         /* Broadcast frames must carry saddr and daddr fields */
1273         if (info->caddr == CBROADCAST) {
1274                 if (skb->len < sizeof(struct test_frame)) {
1275                         IRDA_DEBUG(0, "%s() test frame to short!\n",
1276                                    __FUNCTION__);
1277                         return;
1278                 }
1279
1280                 /* Read and swap addresses */
1281                 info->daddr = le32_to_cpu(frame->saddr);
1282                 info->saddr = le32_to_cpu(frame->daddr);
1283
1284                 /* Make sure frame is addressed to us */
1285                 if ((info->saddr != self->saddr) &&
1286                     (info->saddr != BROADCAST)) {
1287                         return;
1288                 }
1289         }
1290
1291         if (command)
1292                 irlap_do_event(self, RECV_TEST_CMD, skb, info);
1293         else
1294                 irlap_do_event(self, RECV_TEST_RSP, skb, info);
1295 }
1296
1297 /*
1298  * Function irlap_driver_rcv (skb, netdev, ptype)
1299  *
1300  *    Called when a frame is received. Dispatches the right receive function
1301  *    for processing of the frame.
1302  *
1303  * Note on skb management :
1304  * After calling the higher layers of the IrDA stack, we always
1305  * kfree() the skb, which drop the reference count (and potentially
1306  * destroy it).
1307  * If a higher layer of the stack want to keep the skb around (to put
1308  * in a queue or pass it to the higher layer), it will need to use
1309  * skb_get() to keep a reference on it. This is usually done at the
1310  * LMP level in irlmp.c.
1311  * Jean II
1312  */
1313 int irlap_driver_rcv(struct sk_buff *skb, struct net_device *dev,
1314                      struct packet_type *ptype)
1315 {
1316         struct irlap_info info;
1317         struct irlap_cb *self;
1318         int command;
1319         __u8 control;
1320
1321         /* FIXME: should we get our own field? */
1322         self = (struct irlap_cb *) dev->atalk_ptr;
1323
1324         /* If the net device is down, then IrLAP is gone! */
1325         if (!self || self->magic != LAP_MAGIC) {
1326                 dev_kfree_skb(skb);
1327                 return -1;
1328         }
1329
1330         /* We are no longer an "old" protocol, so we need to handle
1331          * share and non linear skbs. This should never happen, so
1332          * we don't need to be clever about it. Jean II */
1333         if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) {
1334                 IRDA_ERROR("%s: can't clone shared skb!\n", __FUNCTION__);
1335                 dev_kfree_skb(skb);
1336                 return -1;
1337         }
1338
1339         /* Check if frame is large enough for parsing */
1340         if (!pskb_may_pull(skb, 2)) {
1341                 IRDA_ERROR("%s: frame to short!\n", __FUNCTION__);
1342                 dev_kfree_skb(skb);
1343                 return -1;
1344         }
1345
1346         command    = skb->data[0] & CMD_FRAME;
1347         info.caddr = skb->data[0] & CBROADCAST;
1348
1349         info.pf      = skb->data[1] &  PF_BIT;
1350         info.control = skb->data[1] & ~PF_BIT; /* Mask away poll/final bit */
1351
1352         control = info.control;
1353
1354         /*  First we check if this frame has a valid connection address */
1355         if ((info.caddr != self->caddr) && (info.caddr != CBROADCAST)) {
1356                 IRDA_DEBUG(0, "%s(), wrong connection address!\n",
1357                            __FUNCTION__);
1358                 goto out;
1359         }
1360         /*
1361          *  Optimize for the common case and check if the frame is an
1362          *  I(nformation) frame. Only I-frames have bit 0 set to 0
1363          */
1364         if (~control & 0x01) {
1365                 irlap_recv_i_frame(self, skb, &info, command);
1366                 goto out;
1367         }
1368         /*
1369          *  We now check is the frame is an S(upervisory) frame. Only
1370          *  S-frames have bit 0 set to 1 and bit 1 set to 0
1371          */
1372         if (~control & 0x02) {
1373                 /*
1374                  *  Received S(upervisory) frame, check which frame type it is
1375                  *  only the first nibble is of interest
1376                  */
1377                 switch (control & 0x0f) {
1378                 case RR:
1379                         irlap_recv_rr_frame(self, skb, &info, command);
1380                         break;
1381                 case RNR:
1382                         irlap_recv_rnr_frame(self, skb, &info, command);
1383                         break;
1384                 case REJ:
1385                         irlap_recv_rej_frame(self, skb, &info, command);
1386                         break;
1387                 case SREJ:
1388                         irlap_recv_srej_frame(self, skb, &info, command);
1389                         break;
1390                 default:
1391                         IRDA_WARNING("%s: Unknown S-frame %02x received!\n",
1392                                 __FUNCTION__, info.control);
1393                         break;
1394                 }
1395                 goto out;
1396         }
1397         /*
1398          *  This must be a C(ontrol) frame
1399          */
1400         switch (control) {
1401         case XID_RSP:
1402                 irlap_recv_discovery_xid_rsp(self, skb, &info);
1403                 break;
1404         case XID_CMD:
1405                 irlap_recv_discovery_xid_cmd(self, skb, &info);
1406                 break;
1407         case SNRM_CMD:
1408                 irlap_recv_snrm_cmd(self, skb, &info);
1409                 break;
1410         case DM_RSP:
1411                 irlap_do_event(self, RECV_DM_RSP, skb, &info);
1412                 break;
1413         case DISC_CMD: /* And RD_RSP since they have the same value */
1414                 irlap_recv_disc_frame(self, skb, &info, command);
1415                 break;
1416         case TEST_CMD:
1417                 irlap_recv_test_frame(self, skb, &info, command);
1418                 break;
1419         case UA_RSP:
1420                 irlap_recv_ua_frame(self, skb, &info);
1421                 break;
1422         case FRMR_RSP:
1423                 irlap_recv_frmr_frame(self, skb, &info);
1424                 break;
1425         case UI_FRAME:
1426                 irlap_recv_ui_frame(self, skb, &info);
1427                 break;
1428         default:
1429                 IRDA_WARNING("%s: Unknown frame %02x received!\n",
1430                                 __FUNCTION__, info.control);
1431                 break;
1432         }
1433 out:
1434         /* Always drop our reference on the skb */
1435         dev_kfree_skb(skb);
1436         return 0;
1437 }